Lab 3: Vector Analysis

Goal: The goals of this lab were to 1) learn how to use a number of geoprocessing tools for vector analysis and apply them to determine a suitable habitat for bears in an area of Marquette County, Michigan, 2) generate a data flow model, and 3) introduce a brief lesson on how to use python.

Background: Using GPS coordinates of bear locations within the study area of Marquette County, we must determine which forest types the bears are most commonly found in, how many of them are found near streams, the areas where the forest types intersect with Michigan DNR managed land, and how to eliminate areas that are near urban and built up lands.

Methods: The bear locations were saved in an excel file that contained its X and Y coordinates. Since these coordinates were not in a spatial database, they had to be added to ArcMap as an "event theme" which temporarily displays them as X,Y data. Once these locations were mapped, they had to be exported and brought into the geodatabase as a feature class. The next step was to determine what land cover type each bear location fell into in order to figure out which habitat type the bears were most commonly found in. A simple, inside spatial join brought together the bear locations and the land cover types tables. A summarize of the Minor_Type field (forest type) showed that most of the bears were located in either mixed forest land, forested wetlands, or evergreen forest land. Selecting these land types and creating a new layer from the selection produced the bear_landcover feature class (Figure 1).
The next step was to determine how many bears were found within 500 meters of streams. A 500 meter buffer of the streams produced the feature class streams_500m which was then dissolved to become streams_500m_dissolve. From this analysis, we found that 72% of bears were found within 500 meters of streams.
Based on the criteria we found up to this point (bear_landcover and streams_500m_dissolve), we now wanted to find suitable areas of bear habitat. This was done by performing an intersect between the two previously mentioned feature classes which then produced bear_streams_landcover. Since there were internal boundaries within this result, I used the dissolve tool to remove these boundaries which then resulted in the bear_streamlandcover_dissolve feature class.
Now that the suitable land was determined, I needed to figure out which sections of this land intersected with DNR managed lands. I added the dnr_mgmt shapefile to ArcMap and performed a clip with study_area to produce dnr_studyarea which showed the DNR managed lands located within the study area. Then I intersected dnr_studyarea with bear_streamlandcover_dissolve which resulted in the feature class dnr_bear_streamland.
The final objective was to exclude the areas that were within 5 kilometers of urban or built up land. My first step was to use select by attributes using landcover as the layer, Major_Type as the field, and "urban or built up areas" as the value. I then created a layer from this selection to give me the urban feature class. Next, I put a 5 kilometer buffer on this feature class to give me urban_5km. Finally, I used the erase tool to perform an erase between dnr_bear_streamland (input) and urban_5km (erase features) which resulted in the bear_habitat_final feature class.
After this was complete, I was introduced to python and briefly explored its functionalities. Using python, I performed a few function including buffer, intersect, and erase which can be seen below (Figure 2).
           

Figure 1: Data Flow Model

Figure 2: Python code

Results:

Figure 3: Map of Suitable Bear Habitat in Marquette County, MI

 The final suitable bear habitat areas on the upper map in Figure 3 appear in a golden color. As you can see, these areas are few and not very large in size. The cream colored sections (Land Cover/Stream) show the intersection of suitable land cover types and proximity to streams. The dark blue jagged lines represent the streams and the red dots are the locations of the bears. The outline of the upper map is the study area that appears in red on the lower location map where Marquette County appears in light green around the study area and both are located in the upper peninsula of Michigan.

Sources:

 (n.d.). Retrieved December 4, 2015, from http://gis.michigan.opendata.arcgis.com/  

Michigan 1992 NLCD Shapefile by County. (n.d.). Retrieved December 4, 2015, from http://www.mcgi.state.mi.us/mgdl/nlcd/metadata/nlcdshp.html 

Wildlife_mgmt_units. (n.d.). Retrieved December 4, 2015, from http://www.dnr.state.mi.us/spatialdatalibrary/metadata/wildlife_mgmt_units.htm 

Michigan Geographic Framework: Marquette County. (n.d.). Retrieved December 4, 2015, from http://www.mcgi.state.mi.us/mgdl/framework/metadata/Marquette.html